That's my theory.

Source: Tatoeba

What do you base your theory on?

Source: Tatoeba

A theory must be followed by practice.

Source: Tatoeba

The book is full of far-flung theories without any basis in scientific fact.

Source: Tatoeba

The Greeks invented a theoretical model of geometry.

Source: Tatoeba

The explanation below was achieved by comparing and contrasting a variety of different theories.

Source: Tatoeba

Your theory has no scientific basis.

Source: Tatoeba

I can't find a single flaw in his theory.

I can't find anything wrong with his theory.

Source: Tatoeba

Strictly speaking, the theory is not correct.

Source: Tatoeba

I think your basic theory is wrong.

Source: Tatoeba